Looks like you're in the UK. Did you know The Strategist is too? While conditions like polycystic ovary syndrome can cause the growth of such unruly hair, idiopathic hirsutism usually has no underlying cause, other than a higher-than-usual prevalence of androgens i. Women with the condition tend to grow thick, dark hairs on their back, upper-lip, breasts, chin, chest, or tummy, and battling the fuzz as well as the stubble and ingrown hairs associated with removal may lead to frustration and insecurity. While there are treatments available, like a drug called Spironolactone, which blocks androgen receptors and reduces testosterone, or creams like Vaniqa, many are costly.
Empowering Hairy Women
Empowering Hairy Women | Flickr
Like many physical traits, the amount of hair on the buttocks varies from person to person. For the most part, hair on the buttocks is more of a cosmetic feature than a medical one. Your genes determine how much body hair you have, as well as what kind of hair you have, such as color and texture. So, if you have an abundance of hair on your buttocks, your parents most likely passed this trait on to you.
Mum shows off her very hairy body after her husband urged her to stop shaving
Hirsutism is excessive body hair in men and women on parts of the body where hair is normally absent or minimal. It may refer to a "male" pattern of hair growth that may be a sign of a more serious medical condition,  especially if it develops well after puberty. Hirsutism is usually the result of an underlying endocrine imbalance, which may be adrenal , ovarian , or central.
Milena Jonas, from Berlin, Germany, was diagnosed with polycystic ovary syndrome after developing an insulin resistance when pregnant with her daughter in The stay-at-home mum, 31, had suffered from symptoms including irregular periods, only occurring twice-a-year, skin problems, weight gain, tummy pains, depression and hot flushes for years before her diagnosis. Swiss-born Milena also saw hair loss on her head and excess hair growth, known as hirsutism, on her body. Embarrassed about her body hair, for 15 years Milena spent hours daily shaving her armpits, legs and stomach, and sometimes removed the fuzz from her face twice a day. When everything was shaved and it always came back the next day.